1. Field of the Invention
The present invention relates to display apparatuses, and more particularly to a display apparatus that can detect a rotation state of a display unit with respect to an apparatus body by a simple structure.
2. Description of the Related Art
Video cameras, potable phones, etc., with openable/closable display panels are popular. Some of such video cameras have a structure in which a display panel is rotatable (invertible) around a second rotation axis different from a first rotation axis for opening/closing the display panel so that a user easily views a display screen depending on the purpose of use.
To detect an open/close state and an inversion state of the display panel, a mechanical switch is typically used. The mechanical switch switches an electrical connection in accordance with a mechanical operation. The mechanical switch mechanically detects the open/close state and the inversion state of the display panel, and outputs an on/off signal, as a detected result, to an input port of a microcontroller. The microcontroller receives the on/off signal from the mechanical switch, and controls various operations, for example, a display mode, of the video camera. In particular, for example, the microcontroller turns ON the light of the display panel when receiving a signal indicating that the display panel is open, whereas the microcontroller turns OFF the light of the display panel when receiving a signal indicating that the display panel is closed. Also, the microcontroller controls the display panel such that an image is displayed in a mirror state by inverting the image in up/down and left/right directions when receiving a signal indicating that the display panel is inverted to provide easy viewing for a person facing the display panel. Further, when the display panel is closed while being inverted, the microcontroller controls the display panel such that the image is displayed in a normal state by returning the left/right inverted display to the original state while keeping the up/down inverted display.
However, with the above-described configuration using the mechanical switch, an on point or an off point of the mechanical switch may be deviated due to a tolerance of a part, an assembly tolerance of the apparatus, or a variation of a mount position of the switch. It is difficult to adjust the mechanical switch for providing a normal operation. In addition, when the mechanical switch is used, a mechanical structure of the apparatus becomes complicated, a dimensional tolerance becomes limited, and the assembly of the apparatus becomes troublesome.
To address the problems, for example, Japanese Unexamined Patent Application Publication No. 2004-184293 discloses a method of using a magnetic sensor instead of the mechanical switch, and detecting an open/close state of a display panel on the basis of relative positions of a magnet and the magnetic sensor. Using such a magnetic sensor, the above-mentioned problems resulted from the complicated structure of the mechanical switch are addressed.